(1) Field of the Invention
The present invention relates to a stationary spreader which is mounted adjacent a ground surface and which has a dispenser which is preferably, vertically retractable into the stationary spreader when not in use. In particular, the present invention preferably relates to a stationary salt spreader having retractable spreaders which activates when a sensor located in the adjacent road surface detects a temperature below the preset minimum temperature which represents the temperature at which snow and ice will form on the road surface or which is activated recently.
(2) Description of Related Art
The related art shows a variety of spreaders which are intended to be mounted on or connected to a moving vehicle. Illustrative are U.S. Pat. Nos. 1,558,282 to Prang; 1,629,247 to Bailey; 3,388,869 to Vissers; 4,166,581 to Hetrick; and 4,577,781 to Braun.
Prang shows a seed sowing and distributing machine which is entirely supported from a removable end gate of a vehicle. The machine includes an auger provided in the bottom of a hopper adjacent a top opening of a discharge pipe. The auger moves the seeds to the opening of the pipe. The seeds are discharged from the pipe and enter a fan casing under the horizontal shelf through an intake opening under the discharge pipe in the top of the fan casing. The fan casing is provided with a discharge spout and is mounted on springs to allow oscillation in order to distribute over an area. The casing contains a rotary blade fan which rotates in order to eject the seeds from the fan casing. The rotation of the auger and the fan and the oscillation of the fan casing are all provided by movement of the wheels of the vehicle on which the machine is mounted.
Bailey shows a seed or fertilizer distribution machine supported by a bracket on an end gate of a vehicle. The machine has a hopper-like casing with a lower tubular-like part which forms a housing for a revolvable, fluted feed-roller. The feed-roller is connected to rotate with a shaft which passes through the end walls of the housing and which is driven by the ground wheel of the vehicle. An adjustable bucket and a cut-off valve over the feed-roller on the shaft allow for regulating the feed of the material by the roller. A distributing spout is mounted immediately below the housing in order to receive the material discharged through an opening in the housing. The distributing spout and casing are pivotably mounted in order to be able to be moved horizontally by chains connected to the shaft.
Vissers shows an apparatus for spreading powdered or granular materials which is supported in a frame which is provided with two ground wheels. The apparatus includes a hopper mounted on a spreading member. The bottom of the hopper has a disc having passage holes which is mounted over another disc having similarly located passage holes. The spreading member consists of a spout extending outward from a bowl which is secured on a moveable shaft to enable the spout to be moved. The shaft extends through the bowl and through the two discs and into the bottom of the hopper where an upside-down-shaped body is mounted to the end of the shaft. The body rotates to cause the agitation of the material.
Hetrick describes a vehicle mounted device for spreading salt on a road surface. The device has a hopper for holding the salt which is connected to a discharge chamber which discharges the salt into a spreader element for spreading salt on the road surface. A valve mechanism is provided for opening and closing the passage between the discharge chamber and the spreader element. The valve mechanism is controlled by a motor which also controls the agitator in the hopper which loosens the salt for easier discharge.
Braun describes an apparatus which collects liquid from the road surface having a sensor to measure the temperature of the liquid on the road surface in order to regulate a device for spreading salt on the road surface. The apparatus is adapted to be mounted on a moving vehicle.
In addition, U.S. Pat. No. 3,540,655 to Hinrichs shows a stationary pavement deicer mounted to a wall adjacent the pavement. The pavement deicer has a spreader and a control means which activates the spreader when the ambient temperature adjacent the spreader is below a set point where ice will form. The spreader includes a hopper for storing the granular material and a conventional electric motor. The spreader is a conventional spreader similar to those normally used for spreading insecticides, herbicides, seeds and fertilizers. The motor of the spreader is connected to a power source which is controlled by the control means. The control means includes a timer having a constant speed motor which is energized when the thermostat and humidistat are both closed and/or when the output switch is closed. The switch ensures that the motor will rotate through one complete cycle after the thermostat and humidistat sense an ice forming condition. The control means can be used to control more than one spreader.
Also of interest is European Patent No. 438,823 to Zweegers which describes a spreading device for granular or powdered materials intended to be moved along the ground surface by a vehicle. The device includes an elongated hopper having a shaft extending in the longitudinal direction in the funnel-shaped lower part of the hopper. Near the center of the hopper, the shaft extends through a housing. The parts of the shaft on either side of the housing are provided with auger blades which have opposed pitches such as to move the granular material toward the housing during rotation of the shaft. A wheel provided with blades is located on the shaft in the housing. The blades of the wheel project downward from the bottom side of the hopper and the lower part of the blades cooperate with the upper part of an endless belt. Behind a rear guide roller of the belt is a gutter shaped spreading means having two throwing arms which pivot horizontally on vertical pivot pins. The arms pivot together in response to the movement of the shaft by means of rods connected to a ring mounted on the shaft.
Also of some interest are U.S. Pat. Nos. 1,212,835 to Steele; 3,889,991 to Hewitt; 4,179,073 to Oosterling et al; 5,340,033 to Whitell; German Patent No. 2,648,906 and German Patent Application No. 2,914,158 both to Braun and European Published Application 0 006 272 to Della Faille d'Huysse.
There remains a need for a stationary spreader having a retractable dispenser which is mounted adjacent the ground surface and which is preferably activated by a temperature sensor which detects the ambient temperature of the surrounding ground surface.